Bearing support for microwave oven antenna

Abstract

A microwave oven having a low friction bearing support for a rotatable microwave feed assembly which includes a primary radiating antenna axially coupled to a cylindrical metal stub that vertically extends from the microwave cavity through an aperture into the waveguide where it is excited by microwave energy. The stub has a bottom cylindrical bore which inserts over a microwave transparent post that extends upwardly through the aperture from a horizontal cross bar suspended by two legs connected to the cavity ceiling. The cross bar may be oblique to the waveguide to centrally and positively align the post in the aperture. The roof of the bore has a downward spherical surface which provides a low friction bearing with the microwave post. The feed assembly also includes a microwave transparent turbine against which a stream of air is directed to rotate the feed assembly.

What is claimed is: 
     
       1. A microwave oven, comprising: a microwave cavity comprising side walls, a back wall, a floor and a ceiling;   a waveguide positioned above said ceiling;   an aperture communicating from said waveguide through said ceiling to said cavity;   a bracket having an arm spaced from said ceiling underneath said aperture, said bracket having a vertical bearing post extending through said aperture into said waveguide;   a metal stub having a hollow bore inserted down over said bearing post for rotatably supporting said stub on said post, said stub extending from said waveguide through said aperture into said cavity;   a primary radiator coupled to the bottom end of said stub in said cavity;   means for energizing said waveguide with microwave energy wherein said stub couples said microwave energy from said waveguide into said cavity for radiation from said primary radiator; and   means for rotating said stub on said post.   
     
     
       2. The oven recited in claim 1 wherein said bracket is microwave transparent. 
     
     
       3. The oven recited in claim 1 wherein said arm is oblique to said waveguide. 
     
     
       4. The oven recited in claim 1 wherein said bore has a roof with a downward extending protrusion for minimizing the area of contact with said post. 
     
     
       5. The oven recited in claim 4 wherein said downward extending protrusion is spherically shaped. 
     
     
       6. The oven recited in claim 1 wherein said bore is tapered. 
     
     
       7. A microwave oven, comprising: a microwave cavity having side walls, a back wall, a floor and a ceiling;   a waveguide positioned above said ceiling;   an aperture in said ceiling communicating with said waveguide;   a microwave transparent cradle comprising two legs and a horizontal cross member, the upper ends of said legs being connected to said ceiling, said cross member extending underneath said aperture spaced from said ceiling;   a microwave transparent bearing post extending vertically upward from said cross member;   a cylindrical rod having a bore extending axially from one end, said bore being inserted over said post for rotatably supporting said rod in vertical disposition from said waveguide through said aperture into said cavity;   a conductor extending horizontally from the bottom end of said rod;   a primary radiator connected to said conductor;   means for energizing said waveguide with microwave energy wherein said energy couples from said rod to said conductor to said primary radiator for radiation into said cavity; and   means for rotating said rod on said post wherein said primary radiator moves in a circular horizontal path in said cavity.   
     
     
       8. The oven recited in claim 7 wherein said cross member is oblique to said waveguide. 
     
     
       9. The oven recited in claim 7 wherein said bore has a downward extending ball-shaped roof for minimizing the area of contact and rotating friction between said rod and said bearing post. 
     
     
       10. The oven recited in claim 7 wherein said bore is tapered. 
     
     
       11. The oven recited in claim 7 wherein said rotating means comprises microwave transparent vanes connected to said conductor. 
     
     
       12. The oven recited in claim 11 wherein said rotating means further comprises means for directing a flow of air against said vanes.